SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '51a9420a59768f1b04a638b47a0b4bb3958b2cba4fa4fb279a277e3ca6f98e65' 
  AND token = '0n0qvvo4vyCRY9nGMymCOUGox3TlKDPbx/wRmT7Z+No=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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