SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e18b9449c75e798566f34874d1b007061748f3d5161226f161a721fb4df53751' 
  AND token = 'AtHyqQuXqX8Ipi/75gELORis+2cls+sKI48ESELdp/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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