SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12fdf09c3dab0fcd0e4003cbc8f0096e963b83815250b3979bff65a2a729440e' 
  AND token = '0e5gp6pZZggG1aIh2+G9rxdAuadczAkKPYJ0qHPkLgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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