SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad8f09ed9bb00f2e41645873b664edfdc9492e1ea3d2d5a7748967d2cec26bd' 
  AND token = 'DDDBT8pBXloDLLIvdzuZFaNAyCB2SreZlBdMQ3PyA2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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