SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b5175bc5c4d8cdd35fa095617fee6cf69e27d194189db76e2f2027a6087c7a' 
  AND token = 'tow+TrbTnkYQPqG1N/Qpy3ohsI+bwtfvfHRu/u+GleY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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