SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a52dd6e731bc32fe838d2291dd5e2e5853187505200ba4ce735cdfa2763d17b' 
  AND token = 'GUhTFTjHA3/rQzNqVJW/wj/vXtMw1t22I/5XVyqQSr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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