SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5114d6b670f032d7c3adc51a9607bec2daf07f025032bc09f231eb6cb8a5a799' 
  AND token = 'CcfrNQU8/B++gfZ3h7drzFJkhJk+FZtqbwY83/m2zvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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