SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'accb825f1886fc658844770a7e560787e5593252cb8b4c9d392aef40a7c1c68a' 
  AND token = 'Q+u77TCfNI6Yr/2+KImfy3LEjuvrLSGbCwYMtpbOANI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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