SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b65c81fa02b9e1957e98b0bbd0e95ba18e259464013130f8c9b6ffb19bacc7da' 
  AND token = 'uf14oEyRSDmzLA3dP9x9eHGzPIBdWuL5MmiSqaxhqzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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