SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd29be706e2331ef0bc4dadb92980d7b3e66ce4cad5b92e7b00e0659d99c3c8f8' 
  AND token = '12fVtDaJaZLWyRqpGdC6gpLgu37ZP8x+jBI9+Teo7xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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