SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca2a9b280a4468067de1a789554348facf4f0b71630ddad654f67f700bd366ab' 
  AND token = 'gUVRSxHBOnY/7tkDJXH1HKNijoW9F147I2yuNszMZCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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