SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f45ef478d5b1756a29b7952e6518b64af9ca2a537bbe2c9867fdc2680f4aba98' 
  AND token = 'KOhYayfVba95gfFCFq2oOOvSfIL7QnHvEHkhNSzS1Rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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