SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72b455a9389d0db4bcb3ef171a276bc898eaf0536208f4ffc7aa0eaa48c0f5a0' 
  AND token = '/mJWnLKKYQJGFg5V39Ned+g2z3M+9UhlmviUKbwue00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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