SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f99ed39ad9fb732ef0f55ff9bc74e7146cb1331df05e2bf326b8ee7b86b45921' 
  AND token = '19gbD0VxYCeGpYBhqUu7YxyCIckicjJFHIiTdov9wmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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