SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0608f8620d3733b3951f5a6626d64ccbb051a072616bf9577588e431c675dba' 
  AND token = '72cDB2vgYowycnKntEz/Inoy7Zksyz566DoBcDmDlSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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