SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aba1938ed66962f222fc5173eb4dab00508dc5224fea98d995a1299cd92b3091' 
  AND token = 'HEGRx91AVrOed3AMLWy+CkaGaUpEIvCaulp75NoVsvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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