SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ffa9a9af891c903fbbdb3ca65172cc2623a1ea82f42b2df342303e95ff88d0f' 
  AND token = 'sUZBpiT+evfii3fwfULNglRHjqTNIBRLmlwIa6VSMqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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