SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79805c3a48bd8a2a1950c511d9361b490661c40748c562be2974352bd57f1f92' 
  AND token = 'Qbn/nyg7ERcCCdvsTirDtT/OuD+DKfh0zFBnWS5TCwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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