SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c243fd32d989f88b6404131def12defcb6a0bae0f2c46574a4c0fa16c42e98ec' 
  AND token = 'JB5MG5xY9i6mZKH4ZS6auianp+VRyGIdYooIleuwVtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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