SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e96e915e12e3d27fdcb41000b4d36c84bd38e3b68ab8fde7df2dbbdd6f298821' 
  AND token = 'wZCWSMxiFiFJJC3lXWxIWhSLaDdPPpF3CiPqTrk6lr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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