SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaaf68c3719afb10151448061d4d9bf1ac2591bf2214853402574a9c593412cb' 
  AND token = 'CDJVkxSFOJbqQl2eVJm7JHEX/Uy64x65Vq4KaFCjZKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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