SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4388ce0ef716e9581bf66793588d7d8b1a26e91123efd73d80f5ed0ce4d2cd48' 
  AND token = 'jCQbDadMDNgoQ1AzjEtej2uKrspJwrkHgREL7IsQGfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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