SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd49d132821605150fec7e66b31344e3142d15135e57f724ee60185889836802' 
  AND token = '0e2PWJ5QwvGPD2kqpYvaJi0NaM+npQlXW/VbKlfkn9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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