SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e709f4b0c85ab70360d52f9f890b32533db0435a4d5d2fc41aa7c88e83d26e' 
  AND token = 'BHVFzkOZnDW1Lzb6SRs49qhacmitZhZC4LjDTAOYLvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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