SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2172a0ac06ce6ec005232619f88bd816a4e47674555cfdc0ac280e4af3ca6fb' 
  AND token = '1JrNPUqsyUEYxD1gIIKve+kc0sG6yeWYy28B9xPpAb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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