SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1d6097c7a249353ce242dbc4bed1072626c71c5eda668e43db73d61bc9c131e' 
  AND token = 'fVBXLAl4+mgW3ba60cwDaxKAepHGxniNnecNkEEGjxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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