SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89200e798d8e2e074011157a0e2b945b9e6cbd488ccd43fb93abc0b5965a345c' 
  AND token = 'xXJzpmd1hI8WV/QKlYjPB0vRsfNDzTZU3gEnYHGjJkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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