SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38b6babfcc2b7832fd68a5d111fb4cdd3808814884ddeb915caa4d767f2674a9' 
  AND token = '5M6cpH+48bv3nkIfCVLc98dqYYZ+YG49Mi580AdGfgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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