SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd21f72bd0e9ccc32a545c6dec6857577dc85edd405b6577b1136f7386215eee4' 
  AND token = 'yYZotNjSV1YvvcWOnIsQW+7p+bBgBGuF1YbjtJlgJo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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