SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef3b22953a4a83589490fc2e0a54191e572365c9589bf7846cd60bba11f5dc63' 
  AND token = 'MxC/6w327tDVlLKSz/VGGF6L+QVYCyFp7nik6NeVCZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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