SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54314dd65865528d657e030b2528b765f5abdf6a405be8cbe42e1e7645b5fff3' 
  AND token = 'B36VtY/NkJKMMJyoDccDLWDIvoFHGrFbNTk4j2Ntl60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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