SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e9e1ca177e5fedb896cf1c14d612d76168986d566506728099aafce64119e05' 
  AND token = '0eUNPcEcrnK1nJ67sJYfZPLUsF12ibCP54Ld5W1yb4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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