SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9e1f7fadfa78f43fa1d57f207c7d042bb4d0de70e048fd5356f86ff73ef849f' 
  AND token = 'paS3AXtQC2tjoCZVir4qdcrQ81Hzr88+I92mtb6ax/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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