SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c23d2401417be4d358854f8481fd828a95ac2cc0676ea0c13708c50e26f7d39' 
  AND token = 'Be2SG+EP3A4RZL2EK8WEKbrimgDv/bPqV5UGqfZFuqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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