SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bebbab70358398e96cbd08dc32bebde9049e3da8246a414ce7cb7637e7b7b557' 
  AND token = 'M4wfjDkt8r0DIlySC/6qNf20PDZFf9JvExJhp7+Er8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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