SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff7546eb2ea949bb19fa42ab7a4f3bfd8ffe700aa832ea95812064529905bc2c' 
  AND token = '1Mevp0Yo85mb0aYsuaQcy7uSYwMjfJtbuMp6TCKNnqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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