SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '975a684720191217bd596d1bbafee2526a37c794215e4f4812f28e36dc9d1fb8' 
  AND token = 'b0Mp2pRoigGj7zgzQdoe1//TrHJeHF9HTTrI0k5BpMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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