SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61fb39effc47fc2421b9de12489c8dda2316ad94de1c3557289830b78090f19' 
  AND token = 'W+/X4uAUEkUqVPw4pv8lV3pzyX3o2/qgBa/6Cg82mKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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