SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fd68b132e6a0010a5d1a6cc2f0cf96c371158944c634e7aea3bd7a8a255588b6' 
  AND token = 'kHThV1xaQInu3re8P4mRhrYAA1UJyBF6BGP5dIIi2QY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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