SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b153591c308643ade45cec4e0aab8bd8c073313c600cb95accbaa5c7372b70d0' 
  AND token = '/KeTUPxGmem/XQT1wd8vnLbsZYTAR4b/XjzMwTPSqWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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