SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88dfb19f21e861bc76969d2b582b5471749d3a6e637a8788b1cd451337b9c6d1' 
  AND token = 'Dt6po1E3gCUBA2N16H/kLzFwDxQ0+8EC1n1EJiRNULo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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