SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e852a0afb47c4115119a946bea6ff4f5644d80bdcedd03f296887744464ca815' 
  AND token = 'MCFOU7tKeFllwyAazMnXP/YFhsPSeq3TthNN1+zhLHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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