SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77814abe5d80ba2ed3df6316bc908c46e9afc38d10c4ac834a4b437876eda9af' 
  AND token = 'R1TR/a0Hv76NYwjM6WE3uI8gx/VJP8IzaNIxPVe4Nzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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