SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '524dce363a1cb39ba98a7d5bb5e7f8a45fc3e50f20692cfbab9a59f8ab4f14dc' 
  AND token = 'RjIebw0mfX97BmAv/ek8gKOeUz+ygRxUP0Ehmv4oq+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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