SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b7be51d0a9542268ffd5332d8cccce62bc989bcdf0c5d788644002c181870175' 
  AND token = 'sd3ZO8hDv+s+SyjxWQv7iSs4rZ2gZOQKvMynmwG0tBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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