SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bb8bf26b6c196b439694e36f88336dd0f271815851b68615eb3462425f40136' 
  AND token = 'PWneNOpZOu6N7FEKMk3cp2lwGOunDYuXe5Qjtm4lQ5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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