SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3b6075e9b4e93f477d8c6703a657ab7e28ee181f616c7e082045382eea0747f' 
  AND token = 'JKk33nQCznrnZdJqN5wnvSzdY+NdmWEq6fcgU0wqVRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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