SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a3d07c6a488800b1937ef1d947c7480d33cddf531d079e752679c36485d142a' 
  AND token = 'A9Cnn2mXisSueI6RMq/MjlojIzDCOlLNo1/CFPIHiUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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