SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21a6ddc2c8ed810b9d822540a38b7f15c9e546bf77fbf186d2ad74c1ef3cb24d' 
  AND token = '2fTpivT6gN3E2c7FO4XuxB3fS/fJRxuSvrpwss95OnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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