SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8aefbc0bbeea85133f2163bfe71ce60c6879a76712b6ef5a1709cab491ea311' 
  AND token = 's5J12MLTnL62qoyC+rqxYcuL+oCZSIdLe5vlPBAMRww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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