SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5085b0dc07e06d56d18865cbdd2388d4c74e5cb1918a5812f5f6a1ee733cc3d2' 
  AND token = 'ElLkXfgBq2qYefcnWVNEPMHKvJf8jmaP+A/DruFHkpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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