SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ae431d878559cfdb92bf1a90653cfe511294756e3bb41c22d3be2864b009d3e' 
  AND token = 'YGmB8UOgb6zdShYMikDuhzZKmCum2qZv6Kw54UPMPBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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