SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9570377b4d6bf8f05d88eb7ceb8874043decde35e43e781fd0692796ce1d2554' 
  AND token = 'NFGTBRotJcxmbispdU2AotD3bHieqyDHsdysQj1CtsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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