SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cbd2043d1ce6054a16495300a168a057dfed16c8b6b3d29a0cc67c42221ddb4' 
  AND token = 'ZXZlhY9/ik/aqYMCEiBj0GjoutkB+JoNjtowpMLi9kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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