SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0afeab59d0b5b81350b0beba667b5ce835861b44f69871f6fbdae7a745f4f83' 
  AND token = 'f1rfU2MJ/IFCiFZdbary9it+bzlZ5oRkpRbxSRRLwag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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