SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbcf91575ddfd128d8589025c29415bac1dbe6a3b66b27e58b94644156051ca1' 
  AND token = 'OR8n1uKSMqq1IK4NGyvomGK2WZGc9Hk5t1ji86BzjIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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