SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82b36bde6dd6c83031dcdc85423bb871850fb891f527c2efba274ea352e4cf9b' 
  AND token = 'ljgCtKGws+f7QKcTRWMPe7hcnjbPUXti2SJXdyMCkMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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