SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f32e4b18e34e97617e3c13e1bafaf82b828611d51815ae229795af4bf957019' 
  AND token = 'LG+8wNM2qXCnk+QacdilF8XLOSR4fg4dx+KT0OORtu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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