SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe531cbfb1457884ac6b265c7d4d6db8a6a7fd2b2c00307710689b414683eda4' 
  AND token = 'sWpZ6nOHDkAsOwTOFho/IuYWFSK3BsEufmgdUllvv50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}