SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51c3ca0a3f9e6afa5371af81da8c1abff8b8a8d8871375b3933a3a2f5163917e' 
  AND token = 'vHnYDXjuQGAQugwlSHwz+SPXC+y1q/9Po5Hu3QOu7JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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