SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f81ddb87239aa878152025f6e9393417fe00b12502353e279ec12adb6da76ab2' 
  AND token = 'pkbZhSJEvpGMRj+eH4IN5+CyE6DewVthiRd/vtVHeFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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