SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c2f6e020cef6841cd7de79d185de39a30bb61f134a6fed4b79d1a1a0307ff95' 
  AND token = 'aiMxH489S/+kPg9HbRrbwWq5UWW4MAx04Pq2Z8CTGSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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