SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0ecfc9f2b376275ad2890dadb7a1a83c048fc581eb556d337e275da5385bf8e' 
  AND token = 'sZ055/mBDs7oqvLcvSHX0nR/+/PtAGSPSqXfkmy4H78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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