SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7695c2081c64de2131d5a67e8d838a9f4de07570faf3a8bc9af2e410936bf45' 
  AND token = '4HxYXQYyMN3k2ANhslENoOP/rDN8XJ7NZPHprzY7DoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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