SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87173d3f4f00c7bd9e699a163a94385ec2c81c27accf0954320bb58fb067a4dd' 
  AND token = 'ulvTS2nneWXvhG2ArHJk4vIGzw8QUIjFFKZCWPOcHKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}