SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3be690c443f1f4a41a1025a446b529576a238a52c3dc6337df7356cb8cb72a84' 
  AND token = 'NIARB22Pap9M5oNdOQy2AaSQsbheNeNOSyNb0C+p1yY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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